Chicks with weak legs

[michelle111]

Last week I went out to feed and water chicks one last time before bed and some of there toes were starting to curl. This seemed like classic calcium deficiency so I quickly baked some egg shells and gave that to them. This seemed to help, but over the next several days quite a few of them started to show weakness in their legs. They don't stand for long and stand very tall when they are walking. I have never had this happen before. I have read some things that suggest a vitamin E or D deficiency but am not sure. Any help would be appreciated.

Thanks!